mCq pCO - Standard + Heat Pump - McQuay

Conditioning: pCO Standard chiller + heat pump User Guide ver. 2.9 02/11/99Fans and fans inverterThe regulation of the coolant condensation temperature will be performed by a series of fansplaced on the condensing coil.There are two digital outputs (one for circuit) (MHP) or four digital outputs (two for circuit)dedicated to the fans.The fans will be operated by pCO on the basis of the HIGH PRESSURE values measured bythe pressure transducers when the unit is working in the Summer functioning mode.If the system has no pressure probes, the fans will be operated according to the relativecompressor (compressors and fans of the same circuit will be started and stopped at the sametime).When the unit works as 'heat pump', fans and compressors of the same circuit will be alwaysoperated and stopped simultaneously.It is possible to select the fans' regulation steps on the basis of the pressure values measuredby the transducers (manufacturer password/global parameters). Set the start and stop valuesas shown in the diagram below:FAN STEPONOFFbarDuring the defrosting cycle the fans relative to the circuit undergoing such a procedure will beforced into the Off status.NUMBER OF TURNS OF THE FANSThe number of turns of the fans can be adjusted by means of an external inverter (throughpCO's dedicated analogue output).The number of turns depends on the 1st pressure probe if there is just one compressor; if yoursystem comprises two circuits and consequently two compressors it is the relative probe ofcircuit that will determine the number of turns of all the connected fans.Select pressure set-point and differential zone (manufacturer password/global parameters) todetermine the min. and max. number of turns of the fans.It is possible to select the LOW NOISE mode: with that you can choose the value that theoutput inverter’s signal is cut.setpointdifferentialbarmin. number ofturns of the fansmax. number ofturns of the fansPag.31/61